Oxidative addition of organic halides to zerovalent palladium complexes containing rigid bidentate nitrogen ligands

Zerovalent complexes of the type Pd(Ar-BIAN)(alkene), i.e. complexes containing the rigid bidentate nitrogen ligands bis(arylimino) acenaphthene (Ar = p-Tol, p-MeOC₆H₄, o-Tol,o,o′-Me₂C₆H₃, o,o′-ⁱPr₂C₆H₃) and an electron-poor alkene have been shown to react with a variety of (organic) halides RX, including methyl, benzyl, aryl, acyl and allylic halides, to give the corresponding square planar divalent Pd(R)X(Ar-BIAN) or Pd(η³-allyl)(Ar-BIAN)]X complexes. The new complexes obtained have been fully characterized and their fluxional behaviour in solution studied by ¹H NMR spectroscopy. The rate of oxidative addition of iodomethane to Pd(p-Tol-BIAN)(alkene) complexes was found to decrease with increasing Pd-alkene bond strength, i.e. dimethyl fumarate fumaronitrile, but oxidative addition to the fumaronitrile complex was accelerated by irradiation with a mercury lamp. Oxidative addition of allylic ha